package com.example.demo.niuke.huawei_b;

import java.util.LinkedList;
import java.util.Scanner;

/**
 * ******************************************************
 *
 * @author liugh9
 * @version 1.0
 * @classname _5提取不重复的整数
 * @description
 * @date 2023/08/30 22:01
 * <p>
 * ******************************************************
 */
public class _5提取不重复的整数 {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String next = in.next();
        LinkedList<Character> res = new LinkedList<>();
        for (int i = next.length() - 1; i >= 0; i--) {
            char curr = next.charAt(i);
            if (!res.contains(curr)) {
                res.add(curr);
            }
        }
        for (Character item : res) {
            System.out.print(item);
        }
    }
}
